Regular Arrays vs. Buffers

[amearka]

Hi

I'm newbie in mql5 codding and can't understand differences between regular arrays (like mostly programming languages) and Buffers! and when it is necessary to using that.
I couldn't find any useful description in Manuals and Google.. I'll appreciate if anyone can describe it.

[William Roeder]

1. Arrays must be manually sized. They have no direction. You must move elements if you want a stack/as-series (set non-series, enlarge the array, set as-series).

2. Buffers are automatically size, are as-series, and elements are moved for you, new elements are set to EMPTY_VALUE (or your designated. They can also draw on the chart automatically.

3. In MT4, buffers and the predefined arrays are all ordered AsSeries. There is a difference between the arrays passed to OnCalculate (e.g. low[]) and the MT4 predefined variables (e.g. Low[].) The passed arrays have no default direction, just like MT5.

4. In MT5, you must set the direction.

   To define the indexing direction in the time[], open[], high[], low[], close[], tick_volume[], volume[] and spread[] arrays, call the ArrayGetAsSeries() function. In order not to depend on defaults, call the ArraySetAsSeries() function for the arrays to work with.
             Event Handling / OnCalculate - Reference on algorithmic/automated trading language for MetaTrader 5

[amearka]

William Roeder:

1. Arrays must be manually sized. They have no direction. You must move elements if you want a stack/as-series (set non-series, enlarge the array, set as-series).

2. Buffers are automatically size, are as-series, and elements are moved for you, new elements are set to EMPTY_VALUE (or your designated. They can also draw on the chart automatically.

3. In MT4, buffers and the predefined arrays are all ordered AsSeries. There is a difference between the arrays passed to OnCalculate (e.g. low[]) and the MT4 predefined variables (e.g. Low[].) The passed arrays have no default direction, just like MT5.

4. In MT5, you must set the direction.

Many thanks William